So think of it as a test-bed airspace — Page 266, Lesson 338

We’ve just covered the separation rules, so let’s carry that straight into the next set of airspace provisions. First, a quick contrast: in Class F airspace, the provision of advice and information is what you get, and only participating flights are separated. That’s a key phrase — “participating flights.” It means ATC will separate only those aircraft that have actively joined the service, not everyone in the airspace. And Class F itself is considered temporary, established during a trial period while it’s determined whether a full ATC service is applicable. So think of it as a test-bed airspace. Now, SVFR — Special VFR. All classes of airspace which support the establishment of a CTR, a Control Zone, permit flight under SVFR. So wherever you can have a CTR, you can have Special VFR operations. I’ll flag now that SVFR is covered in detail in Chapter 6, Rules of the Air, so we’re just noting its existence and where it applies here. Next, non-radio operations. Classes E, F, and G — that’s E through G — permit VFR traffic to fly without VHF two-way RTF communications. RTF is radiotelephony, the voice radio link. But here’s the catch: in areas where the ATC authority considers that the provision of the alerting service is essential — typically over remote areas or over expansive areas of sea — routes may be established along which, at the appropriate altitude, two-way RTF communications will be available. And traffic will be advised to maintain radio contact with an air traffic services unit. So even in the non-radio classes, there can be designated routes where you’re expected to talk. Now the speed limit. There’s a limit of 250 knots IAS — indicated airspeed — applied to VFR traffic in Class C, and to all traffic in Classes D through G. So Class C: only VFR traffic is capped. Classes D, E, F, G: everyone is capped. And the limit applies only to traffic flying below 10,000 feet, which is FL100 — Flight Level 100. So above that altitude, the 250-knot limit doesn’t bite. Finally, the Flight Information Service, FIS. In Classes C through G, a Flight Information Service is available to aircraft that either request the service, or are otherwise known to ATC. This service provides collision alerts, but it leaves it to the pilot to take the necessary avoiding action, as per the rules of the air. The information considered necessary relating to collision avoidance is known as traffic information. Now, in Classes A and B, FIS is available too, but it’s of a lesser priority than the provision of ATC. And here’s the distinction: where the provision of traffic information is considered to be of the same priority as ATC, the traffic concerned is known as ‘essential traffic,’ and the information relating to such traffic is called ‘essential traffic information.’ So the term ‘essential’ marks traffic that ATC treats as seriously as it treats its own control duties. That brings us to the airspace summary — a table that summarizes the requirements and restrictions of all seven classes of airspace. Let’s look at it together.